Lines of Latitude and Longitude help us to answer a key geographical question:

“Where am I?”

What are Lines of Latitude and Longitude?

Lines of Latitude and Longitude refer to the grid system
of imaginary lines you will find on a map or globe.
PARALLELS of Latitude and MERIDIANS of Longitude
form an invisible grid over the earth’s surface and assist
in pinpointing any location on Earth with great accuracy;
everywhere has its own unique grid location, and this is
expressed in terms of LATITUDE and LONGITUDE
COORDINATES.
Lines of LATITUDE are the ‘horizontal’ lines.
They tell us whether a place is located in the NORTHERN or the SOUTHERN
HEMISPHERE as well as how far North or South from the EQUATOR it is.
Lines of LONGITUDE are the ‘vertical’ lines.
They indicate how far East or West of the PRIME MERIDIAN a place is.
 • The EQUATOR is the 0° LATITUDE LINE.
o North of the EQUATOR is the NORTHERN HEMISPHERE.
o South of the EQUATOR is the SOUTHERN HEMISPHERE.
• Lines of Latitude cross the PRIME MERIDIAN
(longitude line) at right angles (90°).
• Lines of Latitude circle the globe/world in an east-
west direction.
• Lines of Latitude are also known as PARALLELS.
o As they are parallel to the Equator and apart always at
the same distance.
• Lines of Latitude measure distance north or south
from the equator i.e. how far north or south a point
lies from the Equator.
• The distance between degree lines is about 69 miles
(or about 110km).
o A DEGREE (°) equals 60 minutes - 60’.
o A MINUTE (‘) equals 60 seconds – 60”.

• The NORTHERN HEMISPHERE has latitudes between 0° (the equator) and 90°N (The North
Pole).
• The SOUTHERN HEMISPHERE has latitudes between 0° (the equator) and 90°S (The South
Pole).
• Get shorter toward the POLES, with only the equator, the longest; a great circle.
 Significant LINES OF LATITUDE are:

• The Equator which is at 0° degrees.

• The Tropic of Cancer which is at 23° 30’N.
• The Tropic of Capricorn which is at 23° 30’S.

• The Arctic Circle which is at 66° 30’N.

• The Antarctic Circle which is at 66° 30’S.
• The North Pole which is at 90°N.
• The South Pole which is at 90°S.
FRIGID ZONES
Also known as the ‘Polar Regions’.
North Frigid Zone:
• Lies between North Pole and Arctic Circle.
South Frigid Zone:
• Lies between South Pole and Antarctic Circle.
TEMPERATE ZONES
North Temperate Zone:
• Lies between Tropic of Cancer and Arctic Circle.
South Temperate Zone:
• Lies between Tropic of Capricorn and Antarctic
Circle.
TORRID ZONE
Also known as ‘The Tropics’.
• Lies between the Tropic of Cancer and Tropic
Capricorn.
Also divided into:
North Torrid Zone:
• Lies between the Equator and Tropic of Cancer
South Torrid Zone:
• Lies between the Equator and Tropic of
Capricorn.
The Equator
• The Equator is located at 0° (zero degrees) latitude.
• The Equator is 40,075.16 km long (24,901.55 miles).
• The Equator divides Earth into the Northern and Southern
Hemispheres.
• On the Equator, the sun is directly overhead at NOON on
the two equinoxes (@ 21st June, @21st December).
• Locations north of the Equator have latitudes between 0°
(the equator) and 90° N (the North Pole).
• Locations south of the equator have latitudes between 0°
(the equator) and 90° S (the South Pole).
• On the Equator, the length of DAY and NIGHT are equal
every day of the year.
o The DAY is always twelve hours long.
o The NIGHT is always twelve hours long.
The Tropic of Cancer
• It is an imaginary LINE OF LATITUDE circling the
Earth at approximately 23.5°N (23° 30’N) north
of the equator.
• It passes through more cities than the Tropic of
Capricorn.
o Hawaii, portions of Central America,
northern Africa, the Sahara Desert and near
Kolkata, India.

The Tropic of Capricorn

• It is an imaginary LINE OF LATITUDE circling the
Earth at approximately 23.5°S (23° 30’S) south of
the equator.
• It passes mainly through water; but crosses
through or is near places like Rio de Janeiro in
Brazil, Madagascar and Australia.
The Tropic of Cancer and Capricorn
• The area south of the TROPIC OF CANCER and north of the TROPIC OF CAPRICORN is known as
THE TROPICS (also TORRID ZONE) because the climate is consistently warm all year due to the
sun's angle.
• When it is summer south of the TROPIC OF CAPRICORN, it is winter north of the TROPIC OF
CANCER, and vice versa.

Which ‘1’ is first?

When trying to remember which
TROPIC is in the Northern
Hemisphere and which in the
Southern go ‘alphabetically’:

CANCER
comes before
CAPRICORN

In the NORTH: Tropic of Cancer

In the SOUTH: Tropic of Capricorn
The Arctic Circle
• The ARCTIC CIRCLE, a line of latitude, begins at 60° North and marks the start of the area where
for at least one day each year the sun DOES NOT completely set (June 21) or rise (December 22).
• Animals including polar bears, reindeer, musk ox and polar hare are native to this region.
• Even though the ARCTIC CIRCLE and the ANTARCTIC CIRCLE are polar opposites, the average
temperature at the north pole is higher.
• The LINES OF LONGITUDE that establish our time zones all converge at the pole.

The Antarctic Circle

• The ANTARCTIC CIRCLE is a line of latitude circling the Earth at 66°30’ South.
• The Sun DOES NOT set (December 21-22) or rise (June 21 or 22).
• It separates the South Frigid Zone (Polar Region) from the South Temperate Zone (area between
the Antarctic Circle and the Tropic of Capricorn).

The Arctic and Antarctic Circle

• The Arctic Circle and the Antarctic Circle vary in location slightly because of minor fluctuations in
Earth's axial tilt over time.
• The ARCTIC CIRCLE and the ANTARCTIC CIRCLE are also referred to as the ‘POLAR CIRCLES’.
The North Pole
• There is no land at the North Pole; the nearest land is around 700 miles away - but it is covered in
a thick layer of ice around 6 to 9 feet thick.
• When you are standing on the North Pole, any direction you point is South!
• All the lines of longitude meet at the North Pole.
• During the summer the sun is always up. The sun rises in March and sets in September.
• The MAGNETIC NORTH POLE is different from the TRUE NORTH POLE.

The South Pole

• The South Pole has a desert climate. Air humidity is near zero. However, high winds can cause the
blowing of snowfall, and the accumulation of snow amounts to about 20 cm per year.
• It almost never gets above 0° C in Antarctica; the highest recorded temperature is 7° F (-13.8° C).
• During the South Pole Winter (late March to late September) it is dark all the time.
• In the summer, it is light 24 hours a day, although the sun is very low in the sky.

The North and South Poles

• The North Pole is located at 90° north - or at a 90° angle from the equator. The South Pole lies at
90° south – or at 90° angle from the equator. Both are technically POINTS but are considered
LATITUDES for geographical purposes.
The ‘Three (3) Norths’ are:
• True North also known as
GEOGRAPHIC NORTH.
• Grid North
• Magnetic North

True North:
This is the point at which the EARTH
rotates which we call NORTH POLE.

Grid North:
As the EARTH is a sphere it is not easy to make a flat map. NORTH on the GRID is in a
slightly different direction on each map.

Magnetic North:
This is what your COMPASS points to. Your compass needle is a magnet that lines itself
up with the EARTH’S MAGNETIC FIELD. Magnetic North is in a different place to the
rotation point. The Magnetic North moves slightly each year.
 • LINES OF LONGITUDE are also known as MERIDIANS
OF LONGITUDE.
• LINES OF LONGITUDE follow a North-South direction.
• LINES OF LONGITUDE unlike LINES OF LATITUDE do
not have the same distance from each other.
• LINES OF LONGITUDE measure distance east or west
of the PRIME MERIDIAN.
• LINES OF LONGITUDE are the farthest apart at the
equator.
• LINES OF LONGITUDE intercept at the North Pole and
the South Pole.
• LINES OF LONGITUDE cross the Equator at right
angles.
• LINES OF LONGITUDE are equal in length.
• LINES OF LONGITUDE are halves of great circles.

• The 0° LINE OF LONGITUDE is the PRIME MERIDIAN also known as the MERIDIAN OF GREENWICH.
• The PRIME MERIDIAN or MERIDIAN OF GREENWICH passes at GREENWICH in England.
• To the EAST the earth is divided from 0° to 180°E.
• To the WEST the earth is divided from 0° to 180°W.
• The INTERNATIONAL DATELINE (IDL) is a LINE OF LONGITUDE located at about 180° East or
West of the PRIME MERIDIAN; it demarcates (separates) one calendar day from the next.
 Where in the world is Athens?
Most people would answer Athens is the capital city of Greece.
Others may query…
Athens, Greece or Athens, Ohio, USA?

Athens is the capital and largest city of Greece. It dominates the Athens is a city in and the county seat of Athens County, Ohio,
Attica region and is one of the world's oldest cities. with its United States. It is located along the Hocking River in the south
recorded history spanning around 3,400 years. eastern part of Ohio.

37.9794500° N, 23.7162200° E 39.3292400° N, -82.1012600° W

Athens, Greece - Coordinates in decimal degrees Athens, Ohio - Coordinates in decimal degrees

37°58’46” N, 23°42’58” E 39°19’45” N, 82°06’04” W

Athens, Greece - Geographical Coordinates Athens, Ohio - Geographical Coordinates
 When deciding which goes first:
Latitude or Longitude; think a l p h a b e t I c a l l y.

Both begin with the letter ‘L’; but…..

look at the second letter in each word...
‘A’ comes before ‘O’ in the Alphabet.
Therefore, when in doubt:
The LATITUDE coordinates are written first,
followed by the LONGITUDE coordinates.
The interception of a latitude line and a longitude line allow us to precisely pinpoint and locate
any specific place.
• The PRIME MERIDIAN is the line of 0⁰ longitude.
• The PRIME MERIDIAN is the starting point for measuring distance both east and west
around the EARTH.
• The PRIME MERIDIAN is arbitrary; that is any longitude/meridian line could have been
chosen.
• US President Chester Arthur at an international convention with representatives from
25 countries agreed to pick a single, standard meridian; they chose the
LONGITUDE/MERIDIAN passing through the Royal Observatory in Greenwich, England.
• The GREENWICH MEAN TIME MERIDIAN became the official international standard of
time in 1884.
• The PRIME MERIDIAN also helps establish the INTERNATIONAL DATE LINE.
• The EARTH’S LONGITUDE measures 360⁰; the PRIME MERIDIAN is at 0⁰ longitude -
half way point is 180⁰ longitude - this 180⁰ MERIDIAN/LONGITUDE LINE is commonly
known as the INTERNATIONAL DATE LINE (IDL).
• When passing the INTERNATIONAL DATE LINE you either add a day when going west
or subtract a day when going east.
• The PRIME MERIDIAN and the INTERNATIONAL DATE LINE divide the EARTH into
eastern and western hemispheres in much the same way as the EQUATOR divides the
EARTH into northern and southern hemispheres.
• The EASTERN Hemisphere is EAST of the PRIME MERIDIAN and WEST of the
INTERNATIONAL DATE LINE.
o Asia, Australia and most of Africa are part of the eastern hemisphere.
• The WESTERN Hemisphere is WEST of the PRIME MERIDIAN and EAST of the
INTERNATIONAL DATE LINE.
o The Americas, the western part of the British Isles (including Ireland and
Wales) and the north western part of Africa are in the western hemisphere.
• The PRIME MERIDIAN also sets UTC (Coordinated Universal Time).

Note:
• UTC never changes for daylight savings.
• UTC is the STANDARD OF TIME worldwide NOT a TIME ZONE. (officially: 1972)
• All countries and regions measure their time zones according to UTC.
• There are 24 TIME ZONES in the world.
At the Royal Observatory in Greenwich, England, a brass strip marks zero degrees
longitude. The Western Hemisphere is on one side, the Eastern Hemisphere is on the other.
Photograph by Bruce Dale
This 24-hour clock displays Greenwich Mean Time (GMT), upon which the International
Time Zone system is based. With the annual publication of the "Nautical Almanac" by the
British in 1767, navigators using a marine chronometer and sextant could find their
longitude in relation to the Greenwich meridian. Map and chart makers soon began to base
their calculations on Greenwich, which remains the prime meridian today.
Photograph by Jodi Cobb
 The Royal Observatory at Greenwich, London The Greenwich Meridian, London

GMT:
• Greenwich Mean Time; is a TIME ZONE.
• Prior to 1972 GMT was A TIME STANDARD; after 1972 GMT became a TIME ZONE.
• Shares the same current time with UTC.
• The TIME ZONE is presently in use during ‘standard time’ (non-daylight saving time)
in Europe, Africa, Antarctica, North America.

UTC:
• Coordinated Universal Time; is NOT A TIME ZONE.
• It is A TIME STANDARD that is the basis for civil time and time zones worldwide.
e.g.
o Australian Central Daylight Time (ACDT): UTC +10:30
o Australian Central Standard Time (ACST): UTC +9:30

Coordinated Universal Time in English and Temps universel coordonné in French, was
abbreviated UTC as a compromise between CUT and TUC in English and French, respectively.
Note: The Vernal (Spring) Equinox in the Northern Hemisphere is the Autumnal (Fall)
Equinox in the Southern Hemisphere and vice versa.*
• Equinoxes occur twice a year.
• The name is derived from the LATIN: ‘aequus’ (equal) and ‘nox’ (night) because at the
EQUINOX the night and day are nearly equally long.
• EQUINOXES do not always occur on the same day each year; generally six (6) hours
later each year with a jump of a day. Why does this occur?
o The EARTH takes approximately 365.25 days to orbit the Sun.
 We calculate our year as having 365 days.
 A LEAP YEAR occurs each four (4) years making our 365 day year 366 in
order to make up for the four (4) missing quarters.
• The two (2) EQUINOXES are:
o The Autumn one: AUTUMNAL EQUINOX
o The Spring one: VERNAL EQUINOX
• AUTUMNAL EQUINOX* is the first day of the autumn season when the sun passes the
EQUATOR moving from the Northern to the Southern Hemisphere. (visa versa)
• During the AUTUMNAL EQUINOX* the North Pole begins to tilt away from the sun.
• VERNAL EQUINOX* is the first day of the Spring season when the sun passes the
equator moving from the Southern to the Northern Hemisphere. (visa versa)
• During the VERNAL EQUINOX* the North Pole begins to lean toward the sun again.
Note: Solstices are opposite on either side of the equator, so the winter solstice in the
northern hemisphere is the summer solstice in the southern hemisphere and vice versa.

• SOLSTICES occur when the sun is at its greatest distance from the equator.
• SOLSTICES occur twice a year.
• SOLSTICE derives from two Latin words: ‘sol’ meaning “sun” and ‘sistere’ meaning “to
cause to stand still”.
o The perception that the “sun stands still” comes from the shadow on the sundial
changing minimally on and near the solstices.
• There are two Solstices:
o The Winter Solstice also known as ‘Yule’.
o The Summer Solstice also known as ‘Litha’.
• The WINTER SOLSTICE occurs on or near the 21st of December or 21st of June,
depending on the Hemisphere.
o In the southern hemisphere, the Winter solstice is in June when in the northern
hemisphere it is the Summer Solstice.
• The SUMMER SOLSTICE occurs on or near the 21st of December or 21st of June,
depending on the Hemisphere.
o In the southern hemisphere, the Summer Solstice is in December when in the northern
hemisphere it is the Winter Solstice.
 ASTR 1210 (O'Connell) Study Guide

 Equinoxes

 Geography Glossary

 Prime Meridian

 Time and Date: Equinoxes

 The Equator, Hemispheres, Tropic of Cancer, and Tropic of Capricorn

 What is Latitude and Longitude?